The only person who ever said it was a "security review" was Clinton and her supporters. The FBI had to come out and say "we don't do reviews, we do investigations". They don't investigate for that long spinning their wheels, they do it because they are building a case. If they found nothing the investigation would have been done a long time ago and they wouldn't have offered immunity to anyone.
You don't offer immunity to people if you don't plan on prosecuting. That's just not how it works.
Dancing on the head of a rhetorical pin, huh?
Pagliani asserted his 5th amendment rights which is not an indication of guilt other than among the feeble minded. The FBI granting him immunity is obviously because they want to know what he can tell them.
Reading more than that into it is unwarranted.
